The currently accepted scientific theory that describes the start of our universe is called the Big Bang theory. According to this theory, the universe began as a singularity—an extremely hot and dense state—from which it rapidly expanded and continues to expand to this day.
The Big Bang theory is supported by a wide range of observational evidence, including the observation of the cosmic microwave background radiation, the abundance of light elements, the redshift of galaxies, and the large-scale structure of the universe. These observations indicate that the universe is expanding and that it was once in a highly compressed and hot state.
While the Big Bang theory provides a framework for understanding the early moments of the universe, it does not explain what caused the Big Bang itself or what occurred before it. These remain open questions in cosmology, and scientists continue to explore various ideas and theories to understand the origins and early evolution of the universe.
It's worth noting that our understanding of the early universe is constantly evolving as new observations are made, and scientific theories are refined and expanded.